Magnesium powder is a critical component in a wide variety of applications. Magnesium powders have applications in numerous applications such as signal flares, fireworks, military illuminating and infrared countermeasure flares, propellants, and powder metallurgy. Gas atomized magnesium powders can be used for alloying aluminum and zinc, desulfurization of iron and steel, reduction of titanium through the Kroll process, and incendiaries. However, these powders are pyrophoric and must be handled carefully and kept dry at all times.
One manufacturer of magnesium powder in the United States uses a high pressure gas atomization procedure that utilizes helium doped with small quantities of oxygen as the atomization gas and is executed under an inert atmosphere to reduce (but not eliminate) the potential for dangerous pyrophoric reactions between the atomization gas and molten metal droplets and between the resulting powders and air or moisture (Valimet, Inc. “Preliminary Design of Plant for Spherical Magnesium Powder”, Stockton, Calif., 1996). Similar systems exist in other locations worldwide.
Similar reactivity issues affect the magnesium die-casting industry which has lead to extensive research on methods of protecting magnesium from spontaneous ignition during melting operations and suppressing magnesium vaporization resulting from the metal's extremely high vapor pressure. Recent studies have explored the ability of certain fluorine containing cover gases to protect molten magnesium in die casting operations from excessive vaporization and burning by excluding contact with air by flooding the top of the melt with argon “cover” gas or by modifying the native oxide (MgO) on the melt surface through interaction with these gas atmospheres. Sulfur hexafluoride gas is commonly used in the magnesium casting industry to protect molten magnesium from excessive oxidation and ignition.